how to update rss feed

I am making an rss feed that does not get information from a blog or anything. I am just going to update it by coding.

Is it enough to just insert lines into an .rss file when I update it?

I am planning to just insert these lines into the .rss file under the channel information when I update:

<item>
    <title>This is the title</title>
    <description>This is the description</description>
    <link>http://www.***.com/</link>
  </item>

Code (markup):

Are rss readers going to interpret this the "normal" way? I mean, are all the items under the newest item also going to be interpreted as new items, or is only the injected item going to be interpreted as a new item? Do rss readers remember the older items that it has seen before? If not, maybe it's better to remove old items at and at the same time I'm inserting the new item, so that the rss readers don't believe I have hundreds of new items that really are old items.

 

RSS is good for seo also if we update the RSS daily this is good for Google indexing..